$\frac{\left(n+1\right)\left(2-n\right)\left(5-n\right)}{n\left(n+3\right)\left(2n-1\right)}$

$\frac{h}{5}+\frac{2}{k}$

$x^2-15x+13$

$2y+8y-7+3y$

$\frac{x}{1-\sqrt{2x+1}}$

$\lim_{t\to2}\left(\frac{\sqrt{3+t}-\sqrt{5}}{\sqrt{5}-\sqrt{t^2+1}}\right)$

$\int_0^7\frac{\left(x^2\right)}{\left(7+2x\right)^2}dx$